I have no had any Jaycos but I bought a Coromal Magnum 511 XC last year. Yes it cost us $3k or more for the HWS but to be fair that includes an external shower, second 90 L water tank and the gas fitting and 12 volt and 240 volt wiring etc. I did grumble a bit when we ordered this upgrade, but it is very good!
The Coromal XC offroad (which we have) has additional fixings inside the exterior wall for the cupboards mountings. Also, getting mine ready for a trip in 2 weeks, I have found that whenever I am given a suggestion to harden it up, that when I check it out, Coromal have already been there. eg. Fridge is correctly fitted to Dometic specs, Some cupboards have full length aluminium angles in the corners instead of plastic blocks, good attention to sealing any pipes going through the floor etc. Also, the tyres are 32" 265/75 R16 same as my truck which is running tres 3" larger than stock.
Electrical fitout and the like as standard is very comprehensive and I have not picked up many ideas from reading the extensive threads on Jayco poptop/campers on this forum as I don't need to do what has been done on other makes!
The fitout is a bit basic by some standards but I think it is worth the money. Being an aluminium frame, ours has a 500 kg weight advantage over other similarly sized vans. The feedback we received from other Coromal owners has all been positive.